内蒙古中西部沙源地影响沙尘暴扩展过程的数值模拟研究

 通过对2002年3月18—22日沙尘暴过程进行的数值模拟及针对内蒙古中西部沙尘源地影响的敏感性试验研究，结果表明, 内蒙古中西部荒漠化草原生态的迅速恶化是2001年前后沙尘天气的频繁发生的部分原因。由于沙源地海拔高度的不同和风速随高度的变化，在沙尘远距离输送过程中可能出现两个不同高度而相互孤立的优势沙尘输送带，分别位于对流层和地面附近。其传输距离、传输速度、影响地区、影响时间存在巨大差异。内蒙古中西部沙源地的起沙主要通过地面附近的沙尘输送带向东、向南传输。其通过对流层的传输随沙尘区的不断扩展而越来越弱，进而被其他更高海拔高度的沙源地起沙所取代。

A Numerical Study on Influence of Sand Source Area in Inner Mongolia on the Dust Storm Expending Process

Based on a numerical study on the dust storm process occurred from March 18 to March 22,2002,the influence of the dust source area in Inner Mongolia on the dust storm extending process was conducted.The results show that the degradation of the desert steppe in Inner Mongolia was a reason causing the frequent appearing of dust storm in northwest China.Owing to the distribution characteristic of terrain height in sand source area and the change of the geostrophic wind with height,two isolated preponderant transporting zones often appear in the dust particle transporting process.One lies in the mid-troposphere while the other closely upon the surface.The transportation speed,distance and their impact area and time are different in the process.The raising dust in Inner Mongolia was transported mainly through the zone upon the surface.Its transportation in troposphere became less and less while the dust storm extended southward and eastward.